Spoof detection by ultrasonic subdermal probe

Abstract

Methods and systems of determining whether an object is alive, and therefore part of a live individual, are described. An object having an outer surface (e.g. a friction-ridge surface of a finger) and internal parts (e.g. tissue layer, papillae, blood vessels, fat, muscle, nail and bone) is scanned by a system having a transmitter, receiver and computer. One such system has a substantially planar piezoelectric transmit-layer, an ultrasonic receiver array having a plurality of receivers, and a platen. The transmit layer is caused to produce an ultrasound plane-wave traveling toward the object residing on the platen. Using the ultrasonic receiver, ultrasonic energy that has been reflected from the object is detected. The detected ultrasonic energy is analyzed to provide an analysis result, and the analysis result is compared to a template. A determination is made as to whether the analysis result and the template are similar, and the object is declared to be alive if the analysis result is determined to be similar to the template.

What is claimed is: 
     
       1. A method of indicating whether an object is part of a living being, the method comprising:
 with an ultrasonic sensor comprising a substantially planar piezoelectric transmit layer, an ultrasonic receiver array having a plurality of receivers, and a platen:
 producing, via the transmit layer, an ultrasound plane wave traveling toward an object proximate the platen, the object having an outer surface and internal structures; 
 detecting, via the ultrasonic receiver, ultrasonic energy that has been reflected from the object; 
 analyzing the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures; 
 
 indicating whether the object is part of a living being based, at least in part, on the analysis result. 
 
     
     
       2. The method of  claim 1 , wherein the analysis result is further indicative of a distance from the outer surface to at least a one of the internal structures. 
     
     
       3. The method of  claim 1 , wherein the analysis result is further indicative of a lapsed time between reflection of ultrasonic energy from the outer surface and reflection of ultrasonic energy from at least one of the internal structures. 
     
     
       4. The method of  claim 1 , wherein the internal structures comprise at least one structure selected from a group of structures comprising a tissue layer, one or more papillae, a blood vessel, fat, muscle, and bone. 
     
     
       5. The method of  claim 1 , wherein the analysis result is further indicative of a plurality of times corresponding to an amount of time between producing the plane wave and detecting ultrasonic energy reflected from at least one internal structure. 
     
     
       6. The method of  claim 1 , wherein the analysis result is indicative of a reflected energy signal ratio. 
     
     
       7. The method of  claim 1 , further comprising comparing the analysis result to a template, the template comprising information relating to reflected ultrasonic energy from the internal structures of at least one finger comprising papillae, blood vessels, fat, muscle or bone or a combination thereof. 
     
     
       8. The method of  claim 1 , further comprising determining an amount of energy reflected by one or more internal structures. 
     
     
       9. An ultrasonic sensor system, comprising:
 a substantially planar piezoelectric transmit layer; 
 an ultrasonic receiver array having a plurality of receivers; 
 a platen; and 
 control electronics configured to:
 produce, via the transmit layer, an ultrasound plane wave traveling toward an object proximate the platen, the object having an outer surface and internal structures; 
 detect, via the ultrasonic receiver, ultrasonic energy that has been reflected from the object; 
 analyze the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures; and 
 indicate whether the object is part of a living being based, at least in part, on the analysis result. 
 
 
     
     
       10. The ultrasonic sensor system of  claim 9 , wherein the analysis result is further indicative of a distance from the outer surface to at least a one of the internal structures. 
     
     
       11. The ultrasonic sensor system of  claim 9 , wherein the analysis result is further indicative of a lapsed time between reflection of ultrasonic energy from the outer surface and reflection of ultrasonic energy from at least one of the internal structures. 
     
     
       12. The ultrasonic sensor system of  claim 9 , wherein the internal structures comprise at least one structure selected from a group of structures comprising a tissue layer, one or more papillae, a blood vessel, fat, muscle, and bone. 
     
     
       13. The ultrasonic sensor system of  claim 9 , wherein the analysis result is further indicative of a plurality of times corresponding to an amount of time between producing the plane wave and detecting ultrasonic energy reflected from at least one internal structure. 
     
     
       14. The ultrasonic sensor system of  claim 9 , wherein the analysis result is indicative of a reflected energy signal ratio. 
     
     
       15. The ultrasonic sensor system of  claim 9 , wherein the control electronics are configured to compare the analysis result to a template, the template comprising information relating to reflected ultrasonic energy from the internal structures of at least one finger comprising papillae, blood vessels, fat, muscle or bone or a combination thereof. 
     
     
       16. The ultrasonic sensor system of  claim 9 , wherein the control electronics are configured to determine an amount of energy reflected by one or more internal structures. 
     
     
       17. One or more non-transitory, computer-readable storage media having instructions stored thereon for performing a method of indicating whether an object is part of a living being, the method comprising:
 with an ultrasonic sensor comprising a substantially planar piezoelectric transmit layer, an ultrasonic receiver array having a plurality of receivers, and a platen:
 producing, via the transmit layer, an ultrasound plane wave traveling toward an object proximate the platen, the object having an outer surface and internal structures; 
 detecting, via the ultrasonic receiver, ultrasonic energy that has been reflected from the object; 
 analyzing the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures; 
 indicating whether the object is part of a living being based, at least in part, on the analysis result. 
 
 
     
     
       18. The one or more non-transitory, computer-readable storage media of  claim 17 , wherein the analysis result is further indicative of a distance from the outer surface to at least a one of the internal structures. 
     
     
       19. The one or more non-transitory, computer-readable storage media of  claim 17 , wherein the analysis result is further indicative of a lapsed time between reflection of ultrasonic energy from the outer surface and reflection of ultrasonic energy from at least one of the internal structures. 
     
     
       20. The one or more non-transitory, computer-readable storage media of  claim 17 , wherein the internal structures comprise at least one structure selected from a group of structures comprising a tissue layer, one or more papillae, a blood vessel, fat, muscle, and bone. 
     
     
       21. An ultrasonic sensor system, comprising:
 means for producing, via a transmit layer, an ultrasound plane wave traveling toward an object proximate a platen, the object having an outer surface and internal structures; 
 means for detecting, via an ultrasonic receiver, ultrasonic energy that has been reflected from the object; 
 means for analyzing the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures; and 
 means for indicating whether the object is part of a living being based, at least in part, on the analysis result. 
 
     
     
       22. The ultrasonic sensor system of  claim 21 , wherein the analysis result is further indicative of a distance from the outer surface to at least a one of the internal structures. 
     
     
       23. The ultrasonic sensor system of  claim 21 , wherein the analysis result is further indicative of a lapsed time between reflection of ultrasonic energy from the outer surface and reflection of ultrasonic energy from at least one of the internal structures. 
     
     
       24. The ultrasonic sensor system of  claim 21 , wherein the internal structures comprise at least one structure selected from a group of structures comprising a tissue layer, one or more papillae, a blood vessel, fat, muscle, and bone. 
     
     
       25. The ultrasonic sensor system of  claim 21 , wherein the analysis result is further indicative of a plurality of times corresponding to an amount of time between producing the plane wave and detecting ultrasonic energy reflected from at least one internal structure. 
     
     
       26. The ultrasonic sensor system of  claim 21 , wherein the analysis result is indicative of a reflected energy signal ratio. 
     
     
       27. The ultrasonic sensor system of  claim 21 , further means for comparing the analysis result to a template, the template comprising information relating to reflected ultrasonic energy from the internal structures of at least one finger comprising papillae, blood vessels, fat, muscle or bone or a combination thereof.